charset.h
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/*
* charset conversion utils
*
* Copyright (c) 2017 Rob Clark
*
* SPDX-License-Identifier: GPL-2.0+
*/
#ifndef __CHARSET_H_
#define __CHARSET_H_
#include <linux/types.h>
#define MAX_UTF8_PER_UTF16 3
/**
* utf16_strlen() - Get the length of an utf16 string
*
* Returns the number of 16 bit characters in an utf16 string, not
* including the terminating NULL character.
*
* @in the string to measure
* @return the string length
*/
size_t utf16_strlen(const uint16_t *in);
/**
* utf16_strnlen() - Get the length of a fixed-size utf16 string.
*
* Returns the number of 16 bit characters in an utf16 string,
* not including the terminating NULL character, but at most
* 'count' number of characters. In doing this, utf16_strnlen()
* looks at only the first 'count' characters.
*
* @in the string to measure
* @count the maximum number of characters to count
* @return the string length, up to a maximum of 'count'
*/
size_t utf16_strnlen(const uint16_t *in, size_t count);
/**
* utf16_strcpy() - UTF16 equivalent of strcpy()
*/
uint16_t *utf16_strcpy(uint16_t *dest, const uint16_t *src);
/**
* utf16_strdup() - UTF16 equivalent of strdup()
*/
uint16_t *utf16_strdup(const uint16_t *s);
/**
* utf16_to_utf8() - Convert an utf16 string to utf8
*
* Converts 'size' characters of the utf16 string 'src' to utf8
* written to the 'dest' buffer.
*
* NOTE that a single utf16 character can generate up to 3 utf8
* characters. See MAX_UTF8_PER_UTF16.
*
* @dest the destination buffer to write the utf8 characters
* @src the source utf16 string
* @size the number of utf16 characters to convert
* @return the pointer to the first unwritten byte in 'dest'
*/
uint8_t *utf16_to_utf8(uint8_t *dest, const uint16_t *src, size_t size);
/**
* utf8_to_utf16() - Convert an utf8 string to utf16
*
* Converts up to 'size' characters of the utf16 string 'src' to utf8
* written to the 'dest' buffer. Stops at 0x00.
*
* @dest the destination buffer to write the utf8 characters
* @src the source utf16 string
* @size maximum number of utf16 characters to convert
* @return the pointer to the first unwritten byte in 'dest'
*/
uint16_t *utf8_to_utf16(uint16_t *dest, const uint8_t *src, size_t size);
#endif /* __CHARSET_H_ */